Information

31.3.3.1 Types of transpose
The CRC module provides several types of transpose functions to flip the bits and/or
bytes (for both writing input data and reading the CRC result, separately using the
CTRL[TOT] or CTRL[TOTR] fields) according to the CRC calculation being used.
The following types of transpose functions are available for writing to and reading from
the CRC data register.
1. CTRL[TOT] or CTRL[TOTR] is 00
No transposition occurs.
2. CTRL[TOT] or CTRL[TOTR] is 01
Bits in a byte are transposed, while bytes are not transposed.
reg[31:0] becomes {reg[24:31], reg[16:23], reg[8:15], reg[0:7]}
15
15
8
7
0
0
7
8
31
31
24
23
16
16
23
24
Figure 31-5. Transpose type 01
3. CTRL[TOT] or CTRL[TOTR] is 10
Both bits in bytes and bytes are transposed.
reg[31:0] becomes = {reg[0:7], reg[8:15],reg[16:23], reg[24:31]}
31
31
0
0
Figure 31-6. Transpose type 10
4. CTRL[TOT] or CTRL[TOTR] is 11
Bytes are transposed, but bits are not transposed.
reg[31:0] becomes {reg[7:0], reg[15:8], reg[23:16], reg[31:24]}
Functional description
K10 Sub-Family Reference Manual, Rev. 6, Nov 2011
744 Freescale Semiconductor, Inc.